Punch



Sept. 5, 1944. 11A'. BENNER PUNCH Filed April 24. 1943 Patented Sept. 5, 1944 UNI TEf-D STAT E S PATENT i0 F FICE PUNCH Dale `A. Benner, Arum, 1u. Application April 24, 1943, Serial No. 484,344

4 claims. 601.1644101) .This invention relates'to punches; and has special reference to a punch bit and screw as- Isembly for use in punches of the general type disclosed in my prior patents, No. 2,202,513 and No.. 2,202,514, granted May;28, 1940.

In the 'portable punches disclosed in said patents, the punch bits are rotatively attached to the inner ends of screw .shafts by rotation of which shafts the punch bits are moved longitudinally with said shafts to perform their inl thereof, and engaging retaining pins secured in thevshafts and extending through saidgrooves for the purpose of preventing withdrawal or detachment of thebits and leaving the bits rotative relative-tothe screw shafts. These circumferential grooves `quite considerably reduce the cross-sectional area or diameter of the bit Shanks, andvsubstantially'weaken the shanks of the bits at the grooves. In vconsequence ofthe tremendous pressures vand forces which are exerted on theends or tips -of the punch bits and which pressures and forces Vare translated or transmitted back to the `weaker points of the bit Shanks-at said grooves, `the bits are sometimes brokenat said weaker points. In addition, it has occurred that the vretaining pins are sometimes broken underthe pressures, stresses and forces whichz'must be overcome when the screw shafts are `rotated and moved longitudinally to Withdraw the punch'bits` from. the holes formed thereby, vresulting in'disalinement of thebits relative to the screw shafts, and sometimes resulting in stripping the threads on said screw shafts. These diiiiculties have presented serious problems in the'satisfactory operation and use of punches having weakened portions created by or resulting from the formation of said circumferential grooves in thebit shanks which receive the retaining pins.

Objects of the present invention are to provide an improved punch screw and bit assembly which will overcome the difficulties mentioned and which haveresulted from the 'presence and existence of the aforesaid circumferential grooves in and around the punch bit'shanks; to' provide ank improved punch screw and bit assembly having the punchbit vmounted `coaxially in the end of the longitudinally movable screw'shaft of a punch lZO ofg-,thergenerali type 'disclosed insaid patents, with .the punchbit shank of uniform diameter and unweakened by 'any circumferential groove, etc., and provided with a circumferential thrust bearing shoulder at the union of the shank andthe punch bit tip engaging against a-rernovable and :replaceable retaining ring mounted in the end of thev screw shaft for preventing outwarolwithdrawal or displacement of the bit `and leaving the bit freely rotative relative to the shaft during rotation vof the shaft in either direction and during longitudinal movement of the fshaft in either direction; and to provide novel means for optionallysupporting bits provided With tips of :different sizes or cross-sectionalareas andshanks of a uniform or datum cross-sectional area in 'connection with the same shaft inia manner to shaft is rotated, and having a coaxial socket in one end, in combination with a bit having a shank rotatively mounted within and having a circumferential shoulder in said socket, and a retaining ring 4or lcollar'removably mountedin the socket and Y,engagingsaid shoulder to retain the bit in connection with the shaft, and means preventing securing of the retaining ring or collar in position in the shaft inany other than a predetermined or datum position for proper cooperation withy the shaft and bit.

Other objects andadvantages of the invention shouldbe apparent from the following description, reference .being made to the.v annexed drawing, in which- Fig. 1 is a side elevation of an improved portable punch having my i present invention embodied therein.

Fig. 2 is ya greatly enlarged longitudinal sectional view showing the principal structural features'of an embodiment of the present invention.

Fig. '3 is a cross-sectional View of the punch shaft, retaining ring, and punch, approximately on the line 3-7'3 of-Fig..2.

Fig.` 4 is an enlarged sectional view showing a Y punch of a different size substituted for the punch of the size that is shown in Fig. 2.

Fig. 5 is a side elevation of the retaining ring detached from the punch.

As shown, theportablefpunch in vwhich the present invention: is-embodiedis of Athe typeidis- 4 is mounted in the end portion 2 and has a bore therethrough. Athreaded shaft 6 is screwed through a threaded hole in the end portion 3 of the frame for rotary and longitudinal movements. The shaft 6 may be equipped with a cylindrical head 'I formed with series of diametrical holes 8 and 9, as disclosed in my said Patent No. 2,202,513, or may be of .other form such as either instance, the shaft 6 may be forcibly rotated, and consequently moved longitudinally, by engagement of an appropriate actuator with that shown in my said Patent No. 2,202,514. In

the head 1 or other formation on the outer end K of said shaft.

The shaft 6 is axially alined with .the die ,4 and with the bore 5 through said die. 'Ine inner end of the shaft 6 is formed with a coaxial bore or well I0 in axial alinement with the bore 5. A

punch bit having a shank II rotatively mounted in the bore or well Ill, has its end abutting against a. bronze thrust bearing disc I2 seated inthe bottom of said bore or well I0. The shank II is formed integra-l with a punch tip I3. A rounded or cavetto shoulder I4, which may be approximately a quarter-round, is formed at the union of the shank II and tip I3. The beginning o-f said shoulder I4 at the outer end of the shank II is approximately even or in alinement with an annular shoulder I5 at the outer end of the bore or well I0. That is, when the shank II is within the bore orv well Il] and in abutting contact with the disc I2, the beginning ofthe shoulder I4 at the outer end of said shank II is even with the internal annular shoulder I5.

A retaining ring I6 has an internal rounded portion I'I at one end complementary to the rounded shoulder I4 on the punch bit. The retaining ring I6 has a non-screwthreaded outer peripheral surface fitting within an extension I8 of the shaft 6 beyond the open end ofthe well or bore I0. The extension I8 has a non-screwthreaded inner surface and receives and supports the ring I6 around the tip I3 of the bit in a relationship in which the rounded or ovolo portion I'I at the end of the ring I6.ts closely against the complementary rounded shoulder I4 at the union of the shank I I and tip I3 of the bit.

A number of holes I9 are formed through the extension I8 in planes transversely of the plane of tne axis of the shaft 6 and of the axis of the bore or well I0. Said holes I9 intersect and open into the cylindrical space in which the ring I6 is received. The ring is formed with peripheral grooves 20 complementary to the holes I9 and arranged to form wall portions of said holes when the ring I 6 is properly located with its rounded end Il fitting against the rounded shoulder I4, but not otherwise. Pins 2I are driven into the holes I9 and the complementary grooves 2B after the ring I6 has been properly located and assembled in connection with the bit and within the extension I8. These retaining pins 2| hold the ring I6 within the shaft 6, prevent rotation of said ring, prevent endwise displacement of said ring relative to the shaft 6 and the punch bit I I-I3, and leave said punch bit I I--I3 freely rotative relative to said ring and relative to said Y ment to the shaft 6.

tory manner. It eliminates the difficulties before mentioned, and substantially prevents breakage and distortion of the bit when said bit is subjected to the severe pressures, stresses and forces applied thereto when in use. All portions of the bit from the end of the shank I I that abut against the bronze thrust bearing disc I2 to the outer or exposed end of the ring I6 are laterally supported and have contacting journal bearing either within the bore or well I0 or Within the ring I6. The objectionable weakening of the bit by grooves, etc. within the shaft 6 is entirely obviated, as a consequence of which breakage and distortion of the bit under the pressures, stresses and forces to which it is subjected are avoided.

As indicated in Fig. 4, the invention is designed and adapted so that bits of various sizes may be mounted and used selectively and interchangeably in the same portable punch device. Bits having tips of diiferent sizes and having Shanks of uniform predetermined or datum size to fit within the bore or Well I0, and provided with tips of sizes other than the size of the tip I3, may be optionally and interchangeably used. Each interchangeable bit has a shank II of the same Vsize and length as the shanks of other bits that are provided for optional and selective attach- The rounded shoulder I4 of each of said interchangeable bits has its beginning in alinement with the shoulder I5 so that, when the part 22 is extended through the ring I6, the rounded inner end portion I'I of the ring I6 lits against the complementary rounded shoulder I4. rlhat is, the shank II and rounded shoulder I4 of each interchangeable bit are of identical size and form, and the parts 22 of all interchangeable bits of reduced sizes fit within the ring I6, just as the complementary portion of the `bit tip I3 fits within the ring I6, as clearly shown and as already explained. A bit tip 23 of reduced cross-sectional area is integral with the end ofthe part 22 of each interchangeable bit, a circumferential shoulder 24 being provided at the union of the part 22 and the reduced bit 23. Thus, all bits are identical with the exception of the'size of the bit tip, and the presence of the rounded shoulder 24 formed on all bits having tips of less size than the maximum size.

The interfltting rounded shoulder I4 and rounded internal portion II positively prevent error in assembly of any bit on or in connection with the shaft 6. That is, it is essential that the rounded portion I1 of the ring be properly placed against the rounded shoulder I4 of the bit in order to aline the grooves 20 with the holes I9, Unless the grooves 20 are alined with the holes I9, said holes are blocked by peripheral portions of the ring I6, and the insertion of the retaining pins 2I is thereby prevented. Therefore, the invention comprises an embodiment of means for preventing error in assembling any of the interchangeable bits including the ring I6 and pins 2| on or in connection with the punch mechanism. The illustration and description of two bits of different sizes is suflicient to enable those skilled in the art to which this invention appertains to understand the extended range of bits of different sizes that may be used on the same punch mechanism, the means for preventing error in assembly, and the means for eliminating weakness in and consequent breakage of the bits.

y It should now be apparent that this invention attains all of its intended objects and purposes 1n a. highly effective and economical manner.

I contemplate such other variations than those specically suggested as may be required to adapt the invention for its various uses, and as are within the scope of the appended claims.

I claim:

1. In a punch including a rotary and longitudinally movable screw shaft having a coaxial socket in one end thereof, and a tubular portion integral with and projecting from the end of said shaft around and having a greater internal diameter than said socket; a punch bit comprising a cylindrical shank journalled in said socket so that said screw shaft can rotate with respect to the punch shank, a cylindrical portion of less diameter and cross-sectional area than said shank integral with and extending outwardly throughV said tubular portion in axial continuation of one end of said shank, a punch tip having the same diameter and cross-sectional area as said cylindrical portion integral with and extending outwardly from axial continuation of the outer end of said cylindrical portion beyond the end of said tubular portion of said shaft, a circumferential shoulder at the union of said shank and said cylindrical portion approximately even with the union of said tubular portion with said shaft; a combined bearing and retaining ring for said bit mounted in said tubular portion around and forming a bearing for said cylindrical portion of said bit and having its inner end engaging said shoulder, and detachable elements in said tubular portion engaging and holding said ring from rotation with respect to the screw shaft in either direction and also from outward displacement.

2. In a punch including a rotary and longitu# dinally movable screw shaft having a coaxial socket in one end thereof; a punch bit comprising a cylindrical shank journalled in said socket for rotation relative to said shaft, a cylindrical portion of less diameter and cross-sectional area than said shank integral with and extending outwardly from axial continuation of one end of said shank, a punch tip integral with and in axial continuation of the outer end of said cylindrical portion, and a rounded cavetto groove shoulder at the union of said portion and said shank; a tubular portion integral with and projecting from the end of said shaft around and having a greater internal diameter than said socket; a combined bearing and retaining ring for said punch bit secured in said tubular portion around and forming a bearing for said cylindrical portion of said bit and having a rounded ovolo intern-al end portion complementary to and engaging against said shoulder to hold said bit from longitudinal displacement, and detachable elements in said tubular portion engaging and holding said ring from outward displacement.

3. In a punch including a rotary and longitudinally movable screw shaft having a coaxial socket in one end thereof; a punch bit comprising a cylindrical shank journalled in said socket so that said screw shaft can have rotation with respect to said punch shank, a cylindrical portion of less diameter and cross-sectional area than said shank integral with and extending outwardly from axial continuation of one end of said shank, a punch tip integral with and in axial continuation ofthe outer end of said cylindrical portion, and an annular shoulder at the union of said portion and said shank; a tubular portion integral with and projecting from the end of said shaft around and having a greater internal diameter than said socket and provided with a non-screwthreaded inner surface; a combined bearing and retaining ring for said punch bit having a nonscrewthreaded outer surface fitting against said inner surface mounted in said tubular portion around and forming a bearing for said cylindrical portion of said bit and having an end portion complementary to and engaging against said shoulder to hold said bit'frorn longitudinal displacement, and detachable elements in said tubular portion of said shaft engaging and holding said ring from rotation with respect to the screw shaft in either direction and leaving said punch bit so that said screw shaft and ring can rotate with respect to the punch bit.

4. In a punch including a rotary and longitudinally movable screw shaft having a coaxial socket in one end, and a tubular portion integral with and projecting from the end of said shaft beyond and having a greater internal diameter than said socket and provided with a non-screwthreaded inner surface; a punch bit comprising a cylindrical shank rotatively journalled in said socket, a punch tip integral with the outer end of said shank, a circumferential shoulder at the union of said shank and said tip, a combined bearing and retaining ring for said bit having generally a non-screwthreaded outer surface tting yagainst said non-screwthreaded inner surface in .said tubular portion around and forming a bearing for said tip and having its inner end engaging said shoulder, and detachable elements in said tubular portion engaging and holding said ring from rotation with respect to the screw shaft in either direction and also outward displacement and leaving said bit so that said shaft and said ring are rotative relative to it.

DALE A. BENNER. 

